that any alternative would
be flammable (there have
been no non-flammable
alternatives to R410A).
Hence, many of the air
conditioning manufacturers have started
to use R32 as an alternative to R410A
(although R32 cannot be retrofitted
into R410A equipment because of its
flammability – albeit low).
FETA’s Cooper again: “Any R32
installation will come under the refrigerant
safety standard BS:EN 378:2016. This
standard specifies how to calculate the
maximum charge size for a system, based
on where it is, what it is and who will be
near it.
“A2L refrigerant installations also
come under the scope of DSEAR – the
Dangerous Substances and Explosive
Atmosphere Regulations (as indeed do all
refrigerant installations). This requires that
a formal risk assessment is carried out for
each installation.”
675
The refrigerant classification
system – created by the American
Society of Heating, Refrigerating
and Air-Conditioning Engineers and
adopted in the UK – is simple to grasp:
refrigerants are defined either as ‘A’ for
lower toxicity or ‘B’ for higher toxicity.
A1 is non-flammable, A2L is lower
flammability, A2 is flammable and
A3 is higher flammability. The same
categorisation rules apply to the ‘B’
classed refrigerants.
None of the flammable refrigerants
(class 2L and above) will ignite if the
concentration level in a room stays
below their lower flammability limit
(LFL). International and European safety
legislation and standards such as
ISO5149 and EN378 define
requirements to remain
far below the lower
flammable limit in
case of accidental
leakage.
Paul Collins
(inset), technical
manager at
Panasonic UK,
believes that safety
concerns surrounding
R32 are overblown: “Not only
is R32 refrigerant a more efficient and
environmentally friendly alternative to
R410A, but it is also equally as safe to use.
HVAC – REFRIGERANTS
Global warming potential
The GWP of R32. Current
industry ‘favourite’ refrigerant
– R410A – has a GWP of 2,088
“There have been concerns surrounding
the fact that R32 gas is partly flammable.
However, it is extremely difficult to
ignite. In the rare case where a fire was to
start, R32 burns at a slower speed than
walking pace – at 6.7 cm/s, as opposed to
propane’s burning velocity of 46 cm/s –
reducing the likelihood of any damage.”
Besides, ultimately, we are going to
have to become more comfortable with
flammable gases in our environment and
the result will be the HVAC industry having
to upskill, says Tim Mitchell, sales director
of air conditioning distributor Klima-
Therm.
“On top of this,” he says, “arguably,
flammability will drive collaboration in the
construction process and will force the
installation of HVAC equipment very much
to the fore on the critical path. As a result,
the days of rushing to finish a job and
moving swiftly onto the next one will have
to end.”
But, provided care is taken during
installation, flammability is not such a
big issue, Mitchell believes. He offers this
analogy: “Flying is inherently dangerous
– hurtling along at hundreds of miles per
hour in a metal tube is not a sensible thing
for humans to do. Yet, flying is one of the
safest modes of transport because the
checks and balances during the plane’s
manufacture, its maintenance procedures
and pre-flight checks make it so.”
The benefits of R32 for charging AC and
refrigeration systems:
● Relatively simple since R32 is a
single-component refrigerant
● Higher efficiency (10% compared
to R410A) yields higher coefficient of
performance/energy efficiency ratio
● 70% lower GWP compared to
R410A
● F-Gas phasedown compliant
● Affordable and readily available
● Easy to handle, reuse and recycle
● Smaller charges result in heat
exchangers and other
components being more compact
● Low flammability (0.306 kg/m3)
● No CFCs, so no ozone depletion
potential
● Reduced charging volume by 30%
compared to R410A
● Delivers better performance at
extreme outdoor temperatures
May 2019 www.operationsengineer.org.uk 21
/www.operationsengineer.org.uk